What you'll do

Find the version and build information for a bug report, inspect bundled component notices, and understand the licence agreement shown at first launch.

Where to find it

Help → About — the About dialog.
The License Agreement dialog appears automatically at launch until you opt out of it.

Step-by-step

The About dialog

Window title About SWMMVis. A header strip across the top, a filterable master list of components on the left, and licence text plus metadata on the right.

The header strip shows, and the Copy environment button copies:

SWMMVis <major>.<minor>.<patch>
Build:    <compile date> <compile time>
Qt:       <Qt runtime version>
OS:       <pretty product name> (<kernel type> <kernel version>)
Arch:     <CPU architecture>

That block is the first thing to attach to a bug report — its tooltip says so (Copy the build / OS / Qt summary to the clipboard).

The dialog opens with Application → SWMMVis GUI selected. The right pane shows the GUI's GPL-3.0-or-later identifier and the complete repository licence, including the copyright notice. The text wraps to the pane width; Copy License copies the complete text. Select another component to inspect its notice, then select SWMMVis GUI to return to the application licence. Drag the divider between the component list and licence pane to resize them. The component column fills the list width; when a name needs more space, use the horizontal scrollbar at the bottom of the list to read it.

Control	What it does
Filter components…	live-filters the component tree by name
a category row	expands or collapses that group
a component row	loads its metadata and licence into the right pane
Copy License	copies the full licence text to the clipboard
Open Homepage	opens the project homepage in your browser
Open Source	opens the upstream source-download URL
Copy environment	copies the header block above

Selecting a component shows Version, Role, License (SPDX identifier), Source (provenance — vcpkg, in-tree, vendored, system) and a Homepage link, with the bundled licence text or notice beneath. A component whose manifest names a missing file shows *(license file not found: …)*; one with no licence declared shows *(no license file declared in the manifest)*.

Components shipped

The list comes from an embedded component manifest. Version and provenance labels can be stale; these are the current manifest entries:

Category	Component	Licence	Provenance
Application	SWMMVis GUI	GPL-3.0-or-later	HydroCouple — openswmm.gui
Engine	Open-Source SWMM Engine	Apache-2.0	in-tree subdirectory
Engine	Robust geometric predicates (Shewchuk)	public domain	vendored under `vendor/predicates/`
Frameworks	Qt 6	LGPL-3.0-only	system or vendor install
Frameworks	QPropertyModel	MIT	vendored sibling project
Geospatial	GDAL / OGR	MIT	vcpkg
Geospatial	PROJ	MIT	vcpkg
Geospatial	GeoTIFF	MIT	vcpkg
I/O	SQLite	public domain	vcpkg
I/O	Expat	MIT	vcpkg
I/O	libxml2	MIT	vcpkg
Numerics	nanoflann	BSD-2-Clause	vcpkg
Numerics	CVODE (SUNDIALS)	BSD-3-Clause	in-tree, when 2D is enabled
Numerics	OpenMP runtime	Apache-2.0 WITH LLVM-exception (libomp)	system

HDF5 is linked for the 2D results reader but does not currently have a manifest entry.

The licence agreement

At launch, SWMMVis shows a modal License Agreement dialog headed SWMMVis — GNU General Public License v3, with the licence text, a Show this agreement on startup checkbox, and two buttons — Yes, I Agree and No, Exit. Declining exits the application immediately.

Unchecking the box suppresses the dialog on later launches. The preference is stored in the application's settings under SWMMVis/LicenseAgreement/showOnStartup; deleting that key brings the dialog back.

FIGURE PLACEHOLDERdocs/manual/images/a06_license_agreement.png

The startup License Agreement dialog

Licensing summary

SWMMVis itself is GPL-3.0-or-later, © 2026 HydroCouple. The current engine repository's LICENSE and the About component manifest identify Apache-2.0; the engine can be used independently of the GUI. Qt 6 is listed under LGPL-3.0.

Some bundled notices are incomplete or stale. The captured Qt entry includes a packaging placeholder for the full licence text. The engine's bundled notice still says MIT, contrary to its current repository licence and manifest. Use the dependency's actual licence files for the complete text; the About notice is not a complete licence archive. Its header reports Qt runtime 6.11.1 in this build, while the static component entry says 6.10.x.

The bundled licence texts are currently a mix of canonical text and pointers to the upstream LICENSE file, and the pointers are clearly marked as such. The version strings come from the manifest rather than from the build system, so a stale version can appear in the dialog even though the linked library is current — check the About dialog against your build environment before quoting a version in a compliance report.

Adding a dependency to the dialog

The dialog reads embedded resources. Updating an entry requires rebuilding the application resources:

Put the upstream licence text in resources/licenses/<name>.txt.
Add a row to resources/about/components.json:

{

"category": "Numerics",

"name": "Eigen",

"version": "3.4.0",

"role": "Linear-algebra primitives",

"homepage": "https://eigen.tuxfamily.org",

"source": "https://gitlab.com/libeigen/eigen",

"spdx": "MPL-2.0",

"provenance": "vcpkg",

"licenseFile": ":/licenses/eigen.txt"

}
Register the file in the About resource bundle under the /licenses prefix.
Rebuild — the entry appears under its category.

Project links

Resource	URL
Report an Issue	https://github.com/HydroCouple/openswmm.engine/issues
Engine repository	https://github.com/HydroCouple/openswmm.engine
GUI repository	https://github.com/HydroCouple/openswmm.gui
Engine API reference	https://www.hydrocouple.org/openswmm.engine
User manuals	https://www.hydrocouple.org/openswmm.engine/d3/dae/manuals.html

The first four are also on the Welcome page's Learn SWMM panel.

Tips and gotchas

Open Source opens the upstream project's download page, not the exact binary you are running. It is the right link for licence redistribution, and the wrong one for "what code is in this binary".
The Copy environment block is deliberately plain text and diff-friendly. Paste it verbatim rather than retyping it.
Two GUI network layers send a user-agent string naming a repository URL that is not the canonical one. Report issues to the address in the table above.